George keith



" March 20, 1928. e. 16,906

.G. KEITH APPARATUS FOR DELIVERING A MIXTURE OF GAS AND AIR originalFiled Sept. 19, 1916 Reissued M 20, 192a UNITED STATES PATENT OFFICE.

GEORGE KEITH, OF LONDON, ENGLAND, ASSIGNOR, .BY DIRECT AND KESNE ASSIGN-MEN'IS, TO JAMES KEITH '8: BLACKMAN COMPANY, OF LONDON, ENGLAND, A BRIT-I 'ISH COMPANY.

APPARATUS FOR DELIVERING A MIXTURE 01: GAS AND Original applicationfiled September 19, 1916, Serial No. 121,030. Divided and applicationfiled May 24,

1917, Serial 1T0. 170,789. Original K051359319, dated December 18, 1917.Application for reissue filed October 10, 1927. Serial No. 225,363.

This invention relates to an improved apparatus for delivering a mixtureof gas and air (or oxygen) for, combustion, for example, in a gas-firedfurnace, oven or other installation, and it has for its primary object.

ployed, the said method consisting in. in-

ecting one ofthe constituents of the mixture and inducing the flow ofthe other constituent, while governing the pressure ofthe inducedconstituent to maintain the pressure proportionate to the resistanceoffered to the flow of the mixture,v whereby variation in the resistanceof the nozzle, of the furnace or the like being fired, or of the flue,may be automatically compensated for, it being understood that variationin the quality of the mixture must otherwise re-- suit from variation inthe resistance to be overcome;

As pointed out in the specification of'copending application Serial No.121,030, variation of the resistance may be due to variable heating upof the mixture before it issues from the nozzle, fluctuation, of thetemperature in the furnace or the like and consequent variation in thecontraction of the products of combustion, introduction or withdrawal ofmaterials. being heated, opening or closing of doors or-of dampers,variations of pressure in the flue, or to other causes; by the presentinvention the efi'ect on the quality of the mixture of all such possiblecauses of variation may be automaticallycompensated for.

The preferred form of governing device employed comprises a diaphragmcasing in which is fitted a thin membrane operatively.

connected with a valve serving to regulate,

the admission to the casing of the induced medium, the compartment ofthe casing at I the backpf the diaphragm being in communication with apoint in the path of flow of pressure obtaining in pose in' view so togovern the gas pressure that the gas is previously-brought to a pressureequal to that prevailing at the final outlet for the products ofcombustion, e. g., to atmospheric pressure, be directlyinto theatmosphere, or to the pressure prevailing in the chimney.

In case the gas pressure is to be maintained at atmospheric resure, theback of the diaphragm may be eft open; if the gas isto be brought to apressure equal to that prevailing in the chimney, the connection fromthe back of the diaphragm may be led to the chimney.

The invention is illustrated by way of example in the accompanyingdrawings in which Figure 1 is a vertical section showing the dia hragmcasing and injector with a connection from the back of the diaphragm, toa point on the delivery side of the in]ector. Figs. 2, 3 and-4 representdiagrammatically threeforms of connection. Fig. 5 is a vertical sectionthrough' the diaphragm caslng. In the construction shown, the governoris designed to govern the pressure of gas gas belng the induced medium,and the injected'medium being air or oxygen. It will be understood,however, that with suitable modification the governing device may beadapted to govern the pressure of the air or oxygen where the inducedmedium is air or oxygen and the injected. medium is gas.

Referring to the drawings, 1 denotes the diaphragm casing in which isfitted a thin membrane 2 wh1ch is preferably disposed in a verticalplane to eliminate the efi'ect of if the final discharge butterfly valveof substantially elliptical.-

form, adapted to be seated on the machined internal surface of acylindrical" valve casing 4 in communication with theas inlet 5-.itbeing understood, however, t. at any suitable form of valve, balanced orotherwise, may be provided.

The valve 3 is so mounted as to be immovable laterally though not liableto be 'ammed with grit or the like, being carried y a hinge pin passinthrough lugs on a bracket member 6 fitte within the casing 4.

The membrane 2 is operatively connected closed 'as' to move the membraneagainst the face of the dia hragm casingthe arrangement being suc as toobviate straining of the: valve.

w The connection between the back of the diaphr Y J and the injector isrepresented by atu -9"which is led to the expansion tube 10 of theVenturi tube and which may terminate flush with the internal'wall of theVenturi tube'with its mouthvfacing acrom -stream,. as' in Fig? 1 and 4",or'may pro'ect ereof-with' itsmouth ac- "stream,.-as. in Fig. 2, or

into the. interior down stream as in Fig, 3, or in any intermediate 7fiositionflccording asit is intended to estab- 1 ressureabovefor belowthat of the the expansiontube having regard a to the" coratlitionsofconstructioni'and open ation'.

v to the back of the governor diaphragm, neednance of the of'thearrangements described i be adopted,v increase or decrease of theresistance ofl'ered to, the flow is instantaneous ly nded to by thegovernor, .the consequential alteration of the pressure of} the gassupply to the in'ector' resulting inmainte mixture. I v

. It is to be understood that the connection not be taken from theexpansionftube .but may be conveniently taken from any int f between theinlet of; the injector an the e 3 burner nozzle,-0r. even from thefurnace i t self, although in the last mentioned case there will be noprovision for compensation in respect of expansionf before'passage ofthe mixture through the nozzle.

To effect the initial adjustment of'the pro- 'portions of gas and air orto effect any desired variation ,in the ad'ustment, a cook 12 or itsequivalent is fitted 1n the connection 11' for deh'vering gas from thediaphragm casing 1 to the injector.

The'cock 13 serves to'regulate the supply of air to the injector;

While the a paratus ularly applica Is for delivering a sel burntuents ofthe mixture, an inlet connection for the induced constituent, and agoverning depoint in the path of the mixture, for autouniformity of,quality of .anda vertically disposed illustrated is articing mixture ofgas and air to gas-fired furnaces, it is to be understood that the invention is not confined to such application, but includes the delivery ofgas and air (or oxygen) in given proportions to ovens, burners or otherins't'allationswhether the mixture to be consumed be self-burnin orotherwise.

If air (or oxygen) be the in need medium, the governing device will, ofcourse, be interposed in theair (or oxygen) inlet connection and willserve to overn the pressure of the air (or oxygen) a mitted, while thegas conection will be taken to the nipple of the injector.

,What I claim is 1. An a paratus for delivering a mixture of gas an acomburent'medium for combustion, comprising, in combination, an injectordevice for injecting one of the constivice interposed in the said inletconnection and adapted to govern the pressure of the induced constituentin dependence on the resistance ofiered to the flow of the mixture, saidlgoverning device comprising 'a valve and a diaphragm connected withsaid valve,

and 'meiins for transmitting to said dia'-- phragm the virtual pressureobtained at a matically controlling theamount of the in ducedconstituent or medium in proportion to the amount of the constituent ormedium delivered by said injector device.' i

I 2. An a paratus for deliverin a mixture of gas an a comburent mediumor combustion, comprising in combination, an injector device forinjecting onset the constituentsof. the mixture, an inlet connection-forthe induced constituent, and a governing device 1 interposed in thesaid-inlet connection and adapted to govern the pressure of the inducedconstituent in de dence on the resistance ofiered to the ow of themixture, saidgov'erning vdevice com rising a valve 1 iaphragmconnected'withfsaid valve,,and means for transmitting-the fluid pressureresulting from the o ration of said injector device to the diap ragm,"ior automatically controlling the amount ofthe induced constituent'ormedium inproportion to the amount ofthe con gstituent-or mediumdelivered by said injector {-deviceilf .3. An apparatus for "deliveringa mixture of gas and a comburent medium for combustion, com rising, incombination, an --m ector device or injection of one of the constituentsof a combustible mixture, an inlet connection for induction of the otherconstituent thereof, and a governing device for governing the'pressure,of the-induced. constituent, said governing device comprising a pivotedvalve insaid inlet connection,

a valve-controlling device comprising a diaphragm forming a part of thewall of said induced constituent of the mixture will be inlet connectionand roviding a chamber automatically regulated in proportion to the atthe outer. side of said diaphragm, a spring fluid pressure of saidmixture. 10 connecting said diaphragm with said valve, In witnesswhereof I have signed my'name 5 and a connection forming a communicationto this specification.

' between said chamber and the path of flow of the mixture; whereby theamount of the I I GEORGE

